Work in this laboratory is devoted primarily to the study of the biochemical mechanisms of the chemotactic response of the polymorphonuclear leukocyte especially in relation to the mechanisms of the other neutrophil functions, phagocytosis, and induced lysosomal enzyme secretion. One of the primary emphases is the investigation of the nature and mode of action of the activatable esterases of the cell. In this regard, the work on the isolation and purification of esterase 1 is being continued. The inhibition profiles of phosphonates ester inhibition of induced lysosomal enzyme secretion and erythrophagocytosis by rabbit polymorphonuclear leukocytes will be obtained. This will be done to see whether the activatable esterase involved in chemotaxis, proesterase 1 is also required in the other functions of the leukocytes. The fractionation and purification of chemotactic factor(s) from culture filtrates of E. coli will be continued. The mechanisms of the volume changes induced by chemotactic factors, and/or cytochalasin B will be further studied.